Field of the Invention
The technical field of the present invention relates to a Group III nitride semiconductor light-emitting device and a production method therefor. More specifically, it relates to a Group III nitride semiconductor light-emitting device exhibiting suppression of metal migration and a production method therefor.
Background Art
In the Group III nitride semiconductor light-emitting device, a p-electrode or an n-electrode is formed of a metal. Metal includes, for example, Ag or Al which causes migration. Migration refers to a phenomenon in which metal atoms contained in a metal material transfer to the surface or the inside of other material such as insulating member when an electric field is applied to a metal material. Therefore, techniques of suppressing metal migration have been developed.
Japanese Patent Application Laid-Open (kokai) No. 2006-24750 discloses a light-emitting device 8 having an n-type layer 2, a light-emitting layer 3, a p-type layer 4, a thin film 7a formed of Pt on the p-type layer 4, an Ag alloy layer 7b on the thin film 7a, a barrier metal layer 7c on the Ag alloy layer 7b, and a p-side bonding layer 7d on the barrier metal layer 7c (refer to paragraphs [0029]-[0078] and FIG. 1). Thereby, Ag migration can be suppressed (refer to paragraphs [0021]-[0023]).
When the barrier metal layer is formed in this way, the method for producing a semiconductor light-emitting device has a step of forming a barrier metal layer. Therefore, a number of steps are required for that step.
On the other hand, the number of steps of the production method is preferably as small as possible. The smaller the number of steps, the shorter the cycle time. That is, the cost can be reduced by reducing the number of steps.
However, a light-emitting device in which migration of Ag atoms or Al atoms is not suppressed, has a short lifetime. Therefore, it is preferable to simplify the production process while suppressing migration of metal atoms.